In Sanskrit, chakra literally means “wheel” or “circle”. However “vortex” or “whirlpool” is a better translation in the yogic context. Chakras or psychic centres are whirlpools of pranic energy at specific areas in the body. The spinning energy centres control the circulation of prana through the body and thus control our physical, mental, and spiritual well-being.
On a physical level, the chakras are associated with major nerve plexuses and endocrine glands. In most of us, these chakras lie dormant and inactive. Concentration on the chakras stimulates energy flow through them and helps activate them. There are seven major chakras and innumerable smaller chakras. The chakras are depicted symbolically as lotus flowers, each having a characteristic colour and a particular number of petals.
Nadi means “flow” or “current”. Like chakras, nadis are not part of the physical body, though they correspond with the nerves. Nadis are subtle channels through which the pranic energy flows. They connect the various chakras.
There are ten major nadis (ancient texts say there are seventy two thousand nadis) out of which the ida, pingala and sushumna are most significant. The most important of these three is the sushumna nadi. This nadi flows through the centre of the spinal cord. The seven major chakras are located along the pathway of the sushumna.